Amir Abdelwahab

An Integrated Management Approach to Atrial Fibrillation.

Background Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia resulting in mortality and morbidity. Gaps in oral anticoagulation and education of patients regarding AF have been identified as areas that require improvement. Methods and Results A before‐and‐after study of 433 patients with newly diagnosed AF in the 3 emergency departments in Nova Scotia from January 1, 2011 until January 31, 2014 was performed. The “before” phase underwent the usual‐care pathway for AF management; the “after” phase was enrolled in a nurse‐run, physician‐supervised AF clinic. The primary outcome was a composite of death, cardiovascular hospitalization, and AF‐related emergency department visits. A propensity analysis was performed to account for differences in baseline characteristics. Results A total of 185 patients were enrolled into the usual‐care group, and 228 patients were enrolled in the AF clinic group. The mean age was 64±15 years and 44% were women. In a propensity‐matched analysis, the primary outcome occurred in 44 (26.2%) patients in the usual‐care group and 29 (17.3%) patients in the AF clinic group (odds ratio 0.71; 95% CI [0.59, 1]; P=0.049) at 12 months. Prescription of oral anticoagulation was increased in the CHADS 2 ≥2 group (88.4% in the AF clinic versus 58.5% in the usual‐care group, P<0.01). Conclusions Adoption of this integrated management approach for the burgeoning population of AF may provide an overall benefit to cardiovascular morbidity and mortality.

NaviStar® ThermoCool® catheter for ventricular tachycardia

Despite the relatively short history of catheter ablation, it has clearly demonstrated high efficacy and safety in treating a wide spectrum of cardiac arrhythmias. An important contributor to this success has been the rapid incorporation of evolving technologies that have changed the practice of electrophysiology remarkably. The introduction of irrigated radiofrequency ablation has allowed electrophysiologists to tackle complex arrhythmias, such as atrial fibrillation and ventricular tachycardia, with a higher success rate. Similarly, the introduction of 3D mapping systems has enhanced our understanding of arrhythmia mechanisms and allowed for integration of electrophysiologic and anatomically guided ablation. In 2006, the US FDA approved the Navistar® ThermoCool® ablation catheter, which incorporates an irrigated tip design with electroanatomical guidance, for ventricular tachycardia ablation. The design of this catheter, its clinical profile, its potential advantages and possible complications associated with its use in ventricular tachycardia ablation are discussed herein.

Ventricular tachycardia ablation in arrhythmogenic right ventricular cardiomyopathy patients with TMEM43 gene mutations: ABDELWAHAB et al.

Catheter ablation of VT in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) is often challenging, frequently requiring multiple or epicardial ablation procedures; TMEM43 gene mutations typically cause aggressive disease. We sought to compare VT ablation outcomes for ARVC patients with and without TMEM43 mutations.

The influence of sex and age on ventricular arrhythmia in a population-based registry

BACKGROUND Post-hoc analyses of clinical trials and population-based studies have shown no difference in mortality between men and women, but often show that men are more likely to receive appropriate ICD therapy. We utilized a population-based registry to investigate the interaction of sex and age and the occurrence of ventricular arrhythmia in an ICD population. METHODS AND RESULTS A total of 776 consecutive patients receiving an ICD for primary or secondary prevention in a provincial ICD registry were studied. No significant mortality difference was found between men and women (27.5% versus 23.7%, p=0.39). Overall, men were more likely to receive appropriate ICD therapy compared to women (39.3% versus 26.7%, p=0.006). The hazard ratio for appropriate therapy in men vs. women <60years of age was 3.22, CI 95% (1.56-6.65), p=0.002, and the same comparison in men vs. women over the age of 60 showed no significant difference (HR 1.11, CI 95% [0.74-1.65], p=0.61). This interaction between age and sex remained significant when adjusted for New York Heart Associated Class, ejection fraction, coronary artery disease and indication for ICD (p=0.02). CONCLUSIONS This study demonstrates that the risk of appropriate ICD therapy increases as women are older, reaching similar risk as men in that age group. Further study of the mechanism of the interaction of age and sex as they modulate the occurrence of ventricular arrhythmia may be warranted.

Polymorphic ventricular tachycardia due to change in pacemaker programming

Introduction Bradycardia is a known risk factor for QT prolongation and polymorphic ventricular tachycardia (polymorphic VT). With the widespread use of pacemakers, it is important to pay attention to different pacing modes while programming pacemakers to avoid bradycardia. We present a case of bradycardia-induced polymorphic VT that occurred after a VDD pacemaker was replaced with a VVIR pacemaker. The lower pacing rate of the new VVIR pacemaker was set at 50 beats per minute (bpm), similar to the old VDD pacemaker. With the absence of atrial tracking in the VVI mode, the patient was paced at the lower pacing rate. The resultant bradycardia caused significant QT prolongation with subsequent polymorphic VT. Increasing the lower pacing rate corrected the QT prolongation and resolved the polymorphic VT.